SPECT in Alzheimer's disease: features associated with bilateral parietotemporal hypoperfusion

OBJECTIVE

To investigate why bilateral parietotemporal hypoperfusion, the typical SPECT pattern of Alzheimer's disease (AD), occurs in some but not in all patients with probable AD.

METHODS

We reviewed the SPECT scans of 220 patients presenting with cognitive impairment. Among them, 104 patients fulfilled NINCDS-ADRDA criteria for probable AD, 48 (32 women) with early onset (before age of 65) and 56 (40 women) with late onset of the symptoms. Dementia severity was assessed by the Mini-Mental State Examination. The SPECT scans were classified by visual inspection blind to clinical diagnoses.

RESULTS

Bilateral parietotemporal hypoperfusion was more frequent in patients with severe AD, in those with early onset of the symptoms, and in men. Duration of symptoms, type of gamma-camera or radiopharmaceutical agent used were not associated with this SPECT pattern.

CONCLUSION

These findings may be useful in the clinical setting and point to heterogeneity of AD according to age at onset.

Increased apolipoprotein B serum concentration in Alzheimer's disease

OBJECTIVE

To investigate the lipoprotein profile in a group of Alzheimer's disease (AD) patients.

PATIENTS AND METHODS

Twenty-four patients with AD and 32 elderly controls were evaluated. Fasting blood samples were obtained for determination of total VLDL, HDL and LDL cholesterol, lipoprotein (a), triglycerides, apolipoprotein A1 and apolipoprotein B.

RESULTS

Significantly higher levels of apolipoprotein B were found in AD patients (P = 0.004), whereas the concentration of lipoprotein (a) and plasma lipids was not statistically different. Apo B levels were similar between AD patients with or without leukoaraiosis on CT scan.

CONCLUSION

AD patients had high serum concentration of apolipoprotein B. This finding suggests that apolipoprotein E may not be the single factor in lipid metabolism to play a role in AD pathogenesis.

Structural correlates of cognitive deficits in a selected group of patients with Alzheimer's disease

OBJECTIVE

The objective of this study was to correlate the densities of neurofibrillary tangles (NFTs) and senile plaques (SPs) in 10 patients with Alzheimer's disease (AD) with comprehensive neuropsychological data obtained within 1 year of death.

BACKGROUND

Clinicopathologic studies in AD have been essentially limited to correlate neuropathologic data with severity of dementia. Very few studies have addressed the correlations between distribution of lesions and specific cognitive deficits. This is partly due to the limitation imposed by the interval between the last neuropsychological evaluation and death.

METHODS

Ten patients with a postmortem diagnosis of AD, with a mean age at death of 80.4+/-6.6 years and a mean duration of symptoms of 5.6+/-2.9 years, were selected for the study. All of these patients were submitted to neuropsychological testing within 1 year of death, including 17 tests assessing memory, language, visuoperceptual, visuospatial, and constructional abilities as well as limb praxis. The neuropathologic study was performed using a modified Bielschowsky technique. Mean densities of SPs and NFTs were determined in the hippocampal formation (CA1, subiculum, and parasubiculum) and in six neocortical areas (midfrontal, orbitofrontal, cingulum, fusiform gyrus, superior and inferior parietal cortices). Statistical correlations were determined between cognitive scores and SP and NFT densities.

RESULTS

For NFTs, significant correlations emerged only between tangle density in CA1 and visuoperceptual scores. For SP density values, significant correlations were found between visuoperceptual tests and lesions in the subiculum and in the fusiform gyrus, significant correlations were found between language scores and SPs in the superior parietal cortex and between visuospatial deficits and lesions in the superior parietal cortex and fusiform gyrus.

CONCLUSIONS

SPs in specific brain areas displayed a good correlation with the cognitive deficits detected in this selected group of AD patients. The association of fusiform gyrus and superior parietal lobule involvement with visuoperceptual and visuospatial deficits, respectively, is in agreement with current knowledge of the anatomic basis of visual processing.

Familial spongiform encephalopathy associated with a novel prion protein gene mutation

Human prion diseases include Creutzfeldt-Jakob disease, Gerstmann-Stráussler-Scheinker disease, fatal familial insomnia, and kuru. Each of these diseases has a specific clinical presentation while spongiform encephalopathy, neuronal loss, and gliosis are their neuropathological hallmarks. We studied a Brazilian family with an autosomal dominant form of dementia. Nine members of the family were affected by a dementia with frontotemporal clinical features, with a mean age at onset of 44.8 +/- 3.8 years and a mean duration of symptoms of 4.2 +/- 2.4 years. Neuropathological examination of 3 patients showed severe spongiform change and neuronal loss in the deep cortical layers and in the putamen, but minimal gliosis in the most severely affected areas. The putamen and cerebellum, but not other areas of the affected brain, displayed prion protein immunoreactivity. A novel prion protein gene mutation causing a nonconservative substitution at codon 183 was identified in 2 neuropathologically confirmed affected individuals (mother and son). The mutation was transmitted in a mendelian fashion to 12 members of the family. Therefore, we identified a novel prion disease variant characterized by an early onset and long duration of the symptoms, severe spongiform change with minimal gliosis, associated with a prion protein gene mutation at codon 183.

Educational level and neuropsychological heterogeneity in dementia of the Alzheimer type

We retrospectively assessed the data from 24 patients with dementia of the Alzheimer type (DAT) who underwent comprehensive neuropsychological evaluations in order to determine whether there is a relationship between neuropsychological heterogeneity and educational level. Postmortem neuropathological examination results were made available for seven cases, confirming the diagnosis of DAT. Thirteen patients had < or = 8 years of schooling (less educated subgroup), and the other 11 had > or = 8 years (higher educated subgroup). There were no significant differences between the two subgroups regarding age and duration of symptoms. Performance within each subgroup was compared with that of a specific set of education-matched elderly controls. In the less educated subgroup, 10 patients evidenced a homogeneous pattern of cognitive impairment, with all cognitive areas being similarly affected. Conversely, 10 higher educated patients had at least one cognitive area relatively preserved in comparison with the others, characterizing a heterogeneous pattern of impairment. These data suggest that a high level of education may lead to a greater capacity to compensate for neuronal damage and determines specific patterns of cognitive impairment in DAT.

Brain SPECT in dementia. A clinical-scintigraphic correlation

The aim of this study was to compare the accuracy of computed tomography (CT) and single photon emission computerized tomography (SPECT) in the diagnosis of dementia. Fifty-two patients with clinical diagnosis of dementia and 11 controls were studied. The scans were interpreted by one experienced neuroradiologist and one nuclear radiologist, both blinded to the clinical data. In the diagnosis of dementia, CT and SPECT showed equal sensitivity (82.7%) and statistically similar specificity (63.8 and 81.8%, respectively). The specificity of SPECT in diagnosing Alzheimer's disease (100%) was statistically superior to CT (69%). However, both methods showed similar sensitivity in detecting Alzheimer's disease. In conclusion, SPECT and CT showed similar accuracy in the diagnosis of dementia. The quite high specificity of SPECT in Alzheimer's disease may be useful for confirming that diagnosis, particularly for patients with presenile onset of the disease.

Neurological examination in obsessive-compulsive disorder

Recent studies suggest the occurrence of a neurological dysfunction in Obsessive-Compulsive Disorder (OCD). The purpose of the present study was to verify the clinical value of a neurological evaluation in patients with the disease. We submitted 15 patients with OCD (five of whom were under clomipramine) and 15 controls in a detailed neurological examination, including assessment of the neurological soft-signs. Eleven patients (73.3 percent) and four controls (26.7 percent) presented abnormalities on examination. The main findings among the patients were: palmomental reflex (six cases); mirror movements (five cases); agraphestesia and dysdiadochokinesia (three cases). Three out of the four patients who had a normal examination were on clomipramine. Palmomental reflex was the main finding among the controls. These results, although preliminary, stress the interest and usefulness of performing a detailed neurological examination in OCD.

[Neuropsychological tests of simple application for diagnosing dementia]

Thirty patients with dementia defined by DSM-III-R criteria (Alzheimer's disease (22), vascular dementia (3), Parkinson's disease, frontal lobe dementia, possible diffuse Lewy body dementia, normal pressure hydrocephalus and uncertain diagnosis), with scores below 24 points in the Mini-Mental Status Examination and more than 4 years of education were submitted to a neuropsychological evaluation. The scores in the neuropsychological tests were compared to those obtained by thirty normal volunteers paired for age, sex and education. Sensitivity, specificity and accuracy of the tests in the distinction of demented and normal volunteers were determined. The accuracies were calculated using ROC curves. Blessed's information-memory-concentration test showed greatest accuracy, followed by copy of simple figures, delayed memory of 10 figures (after 5 minutes), recognition of 10 figures and verbal fluency test (animals). A linear discriminant function, composed by 6 tests: visual perception, incidental memory, delayed memory (after 5 minutes), drawing of a clock, verbal fluency (animals) and calculation tests, was able to discriminate all controls from patients and only one patient was wrongly classified as normal control. These tests were chosen because they can be applied in less than 10 minutes and are very easy to interpret. This discriminant function must be applied in another group of patients and controls in order to demonstrate its value. When associated to the MMSE it may be useful to discriminate patients with dementia from normal people in epidemiological studies.

Wilson's disease: MRI with clinical correlation

We tried to establish possible correlations between clinical data and MRI in a group of patients with Wilson's disease. Eleven patients (6 male, 5 female), aged between 11 and 50 years old, with a duration of illness from 5 months to 32 years, were submitted to MRI on a 1.5 T System. Three patients were asymptomatic, two had mild neurological disturbances, two were moderately affected and the remaining four had a severe form of the disease. All were receiving D-penicillamine at the time of the study. In the most symptomatic patients there were abnormalities in five or more sites on MRI. The putamen was affected in all symptomatic patients, including five with dystonia. A striking feature was the peripheral location of high signal putaminal lesions on T2-weighted images. In five cases, lesions in the corpus striatum or substantia nigra explained the patient's Parkinsonian features. MRI is an efficient method for studying involvement of the central nervous system in Wilson's disease, and allows some interesting anatomoclinical correlations.

Unexpected reading dissociation in a Brazilian "nisei" with crossed aphasia

There is an increased interest in reading impairments in the Japanese language, due to its particular writing system which includes two different scripts, Kanji (logograms) and Kana (phonograms). Reading dissociations between Kanji and Kana have been described, showing that each system is processed differently by the cerebral hemispheres. We describe the case of a 68 year old Brazilian "nisei" (i.e. born from Japanese parents) who had knowledge of both Japanese and Portuguese. He presented an ischemic stroke affecting the right hemisphere and subsequently developed a Broca's aphasia and an unexpected reading dissociation, with an impairment in Kana reading comprehension and a good performance in Kanji and in Portuguese. These findings suggest that the patient's right and left hemispheres have assumed opposite roles not only for oral but also for written language decodification.

[Thrombolytic treatment in pulmonary thromboembolism in the postoperative period following heart surgery complicated by ischemic cerebrovascular attack]

A 69 years old man with pulmonary embolism early after coronary bypass surgery complicated by ischemic stroke received thrombolytic therapy. Reperfusion of the pulmonary artery was achieved. Conversion of the ischemic stroke to hemorrhagic infarction was observed at the CT-Scan without neurological impairment.

Magnetic resonance imaging in intracranial paracoccidioidomycosis

Paracoccidioidomycosis is a systemic mycosis, endemic in South and Central America, that affects the central nervous system (CNS) in almost 10% of patients. Neurological involvement includes two different clinical forms: meningeal and granulomatous, also known as the pseudotumor form. Five patients with biopsy-proved systemic paracoccidioidomycosis and neurological complaints were studied by magnetic resonance imaging. CNS involvement was detected in all patients in the form of multiple round or lobulated lesions, predominantly hypointense on T2-weighted images and ring or nodular enhancement on post-gadolinium T1-weighted images. The lesions were distributed diffusely, with a slight predominance in the supratentorial compartment, although infratentorial lesions were also observed, mainly in the cerebellum. Hypointense lesions on T2-weighted images persisted in all 3 patients reexamined after treatment, whereas enhancing lesions on post-gadolinium T1-weighted images turned isointense in 2 patients. Magnetic resonance imaging is a sensitive method in documenting CNS paracoccidioidomycosis, most frequently as supratentorial and infratentorial multiple, round or lobulated hypointense lesions on T2-weighted images.

Chorea as a sign of systemic lupus erythematosus activity. Case report

Chorea may occur as a neurological manifestation of systemic lupus erythematosus and is often associated with detection of antiphospholipid antibodies. No evidence of chorea as a sign of lupus activity has been established. We describe a patient with systemic lupus erythematosus associated with antiphospholipid antibodies who developed chorea, which has been considered a sign of lupus activity.

Wilson's disease: magnetic resonance imaging (MRI) with clinical correlations in 16 cases

The purpose of this study was to evaluate MRI findings in a group of patients with Wilson's disease, trying to establish possible correlations between clinical and image data. Sixteen patients (8 males and 8 females), with ages ranging from 11 to 50 years, and duration of illness ranging from 5 months to 32 years, were submitted to MRI in a 1.5T System. Four patients were asymptomatic, 4 had mild neurological findings, 2 were moderately affected and the remaining 6 had a severe form of the disease. All patients were receiving D-penicillamine by the time of the study. The most symptomatic patients presented five or more sites of abnormalities on MRI. The putamen was affected in all symptomatic individuals and one asymptomatic and 11 of them presented dystonia on neurological examination. A striking feature was the peripheral localization of putaminal hyperintense lesions on T2 weighted images. In eight cases, striatum or "substantia nigra" lesions explained parkinsonism observed on neurological examination. MRI seems to be an efficient method to study neurological involvement of Wilson's disease allowing some interesting anatomo-clinical correlations.

[Paracoccidioidomycosis of the central nervous system: study of 5 cases by magnetic resonance]

Paracoccidioidomycosis is a systemic mycosis, endemic in South and Central America, that affects the central nervous system in almost 10% of the cases. Neurological involvement includes to different clinical forms: meningeal and granulomatous form, also known as pseudotummoral form. Five patients with intracranial paracoccidioidomycosis were submitted to MR examination in a 1.5T system. All patients presented multiple round or lobulated lesions, hyperintense in T1-weighted images and predominantly hypointese in T2-weighted images. The lesions were distributed diffusely, with a slight predominance in the supratentorial compartment, although infratentorial lesions were also observed, mainly in the cerebellum. All lesions had ring or nodular contrast enhancement. Three patients were reexamined for treatment control, with disappearance of the lesions in two, with persistence of hypointense area in T2-weighted images. MR imaging proves to be a good method to evaluate the neurological involvement in paracoccidioidomycosis, mainly due to its high sensitivity for posterior fossa lesions. Further studies are needed to correlate the MR findings and the changes found in MR examination after treatment.

Brain metastasis of a malignant fibrous histiocytoma of the lung

Sarcomas metastatic to the brain as well as primary malignant fibrous histiocytomas of the lung are very unusual tumors. The authors report a case of a 52-year-old man who presented with neurological symptoms due to cerebral metastasis of a malignant fibrous histiocytoma of the lung and provide a review of the literature on the subject.

Neurological complications after thrombolytic treatment for acute myocardial infarction: emphasis on unprecedented manifestations

We examined 348 patients who underwent thrombolytic treatment for acute myocardial infarction. Nine patients (2.58%) developed neurological complications related directly or indirectly to this procedure. Cerebral hemorrhage occurred in 3 patients; 2 patients had transient ischemic attacks, 1 had syncope, another had psychomotor agitation and 2 patients presented seizures during the infusion of the thrombolytic agent, without hemodynamic abnormalities. This latter feature had never been described before.

Neurosarcoidosis: therapeutic success with methotrexate

Sarcoidosis affects the nervous system in 5% of cases. Treatment with corticosteroids is usually effective. We describe the case of a patient with neurosarcoidosis in which therapy with prednisone failed whereas the result of methotrexate administration was satisfactory.